TY - JOUR

T1 - To be seen or to hide

T2 - visual characteristics of body patterns for camouflage and communication in the Australian giant cuttlefish Sepia apama

AU - Zylinski, Sarah

AU - How, M J

AU - Osorio, D

AU - Hanlon, R T

AU - Marshall, N. J.

PY - 2011/5

Y1 - 2011/5

N2 - It might seem obvious that a camouflaged animal must generally match its background whereas to be conspicuous an organism must differ from the background. However, the image parameters (or statistics) that evaluate the conspicuousness of patterns and textures are seldom well defined, and animal coloration patterns are rarely compared quantitatively with their respective backgrounds. Here we examine this issue in the Australian giant cuttlefish Sepia apama. We confine our analysis to the best-known and simplest image statistic, the correlation in intensity between neighboring pixels. Sepia apama can rapidly change their body patterns from assumed conspicuous signaling to assumed camouflage, thus providing an excellent and unique opportunity to investigate how such patterns differ in a single visual habitat. We describe the intensity variance and spatial frequency power spectra of these differing body patterns and compare these patterns with the backgrounds against which they are viewed. The measured image statistics of camouflaged animals closely resemble their backgrounds, while signaling animals differ significantly from their backgrounds. Our findings may provide the basis for a set of general rules for crypsis and signals. Furthermore, our methods may be widely applicable to the quantitative study of animal coloration.

AB - It might seem obvious that a camouflaged animal must generally match its background whereas to be conspicuous an organism must differ from the background. However, the image parameters (or statistics) that evaluate the conspicuousness of patterns and textures are seldom well defined, and animal coloration patterns are rarely compared quantitatively with their respective backgrounds. Here we examine this issue in the Australian giant cuttlefish Sepia apama. We confine our analysis to the best-known and simplest image statistic, the correlation in intensity between neighboring pixels. Sepia apama can rapidly change their body patterns from assumed conspicuous signaling to assumed camouflage, thus providing an excellent and unique opportunity to investigate how such patterns differ in a single visual habitat. We describe the intensity variance and spatial frequency power spectra of these differing body patterns and compare these patterns with the backgrounds against which they are viewed. The measured image statistics of camouflaged animals closely resemble their backgrounds, while signaling animals differ significantly from their backgrounds. Our findings may provide the basis for a set of general rules for crypsis and signals. Furthermore, our methods may be widely applicable to the quantitative study of animal coloration.

KW - Adaptation, Biological

KW - Animal Communication

KW - Animals

KW - Female

KW - Fourier Analysis

KW - Male

KW - Optical Phenomena

KW - Pigmentation

KW - Sepia

KW - Visual Perception

KW - Journal Article

KW - Research Support, Non-U.S. Gov't

U2 - 10.1086/659626

DO - 10.1086/659626

M3 - Article

C2 - 21508613

VL - 177

SP - 681

EP - 690

JO - American Naturalist

JF - American Naturalist

SN - 0003-0147

IS - 5

ER -